docs: def _fetch_datatype(self, transport, bucket, key, r=None, pr=None,
                          basic_quorum=None, notfound_ok=None,
                          timeout=None, include_context=None):
          """
          _fetch_datatype(bucket, key, r=None, pr=None, basic_quorum=None,
                         notfound_ok=None, timeout=None, include_context=None)
  
  
          Fetches the value of a Riak Datatype as raw data. This is used
          internally to update already reified Datatype objects. Use the
          public version to fetch a reified type.
  
          .. note:: This request is automatically retried :attr:`retries`
             times if it fails due to network error.
  
          :param bucket: the bucket of the datatype, which must belong to a
            :class:`~riak.BucketType`
          :type bucket: RiakBucket
          :param key: the key of the datatype
          :type key: string, None
          :param r: the read quorum
          :type r: integer, string, None
          :param pr: the primary read quorum
          :type pr: integer, string, None
          :param basic_quorum: whether to use the "basic quorum" policy
             for not-founds
          :type basic_quorum: bool
          :param notfound_ok: whether to treat not-found responses as successful
          :type notfound_ok: bool
          :param timeout: a timeout value in milliseconds
          :type timeout: int
          :param include_context: whether to return the opaque context
            as well as the value, which is useful for removal operations
            on sets and maps
          :type include_context: bool
          :rtype: tuple of type, value and context
          """
          _validate_timeout(timeout)
  
          return transport.fetch_datatype(bucket, key, r=r, pr=pr,
                                          basic_quorum=basic_quorum,
                                          notfound_ok=notfound_ok,
                                          timeout=timeout,
                                          include_context=include_context)